On 5/13/14 05:15 , Christian Balzer wrote: > On Tue, 13 May 2014 22:03:11 +1200 Mark Kirkwood wrote: > >> On thing that would put me off the 530 is lack on power off safety >> (capacitor or similar). Given the job of the journal, I think an SSD >> that has some guarantee of write integrity is crucial - so yeah the >> DC3500 or DC3700 seem like the best choices. >> > All my machines have redundant PSUs fed from redundant circuits in very > high end datacenters backed up by the usual gambit of batteries and > diesel monsters. > So while you (and the people who's first comment about RAID controllers is > to mention that one should get a BBU) certainly have a point I'm happily > deploying 530s where they are useful. > > If that power should ever fail, I'm most likely buried under a ton of > (optionally radioactive) rubble (Tokyo here) or if I'm lucky just that one > DC is flooded, in which case the data is lost as well. ^o^ > > Christian > TL;DR: Power outages are more common than your colo facility will admit. In my 15 years, I've experienced 4 data center power outages in 3 different facilities. I don't remember the reason for the first one... maybe a power company transformer failure that went way outside of voltage specs? This was in a "Tier 1" data-center, the day after a press release bragging about their uptime. For the second one, the facility was doing a pressure test of the Halon system. Some pipes failed and dumped halon, which triggered facility power cut. This was in a "Tier 1" data-center. The third and forth were the same root cause in the same facility. The electrical switch that cuts from utility power to UPS power failed half way through the cut over. While replacing the switch (before everything was wired up), a fail-over was accidentally triggered. This was a "Tier 2" data-center. The first two happened before SSDs (although I lost a bunch of HDDs during the Halon deployment). The 3rd power failure had no problems. The 4th power failure killed a mirrored pair of Intel 320's that were connected to a battery backed RAID controller. Both lost their sector map, and had to be erased using the Intel SSD tool before they could be used again. I'm using the DC3700's for my journals. -- *Craig Lewis* Senior Systems Engineer Office +1.714.602.1309 Email clewis at centraldesktop.com <mailto:clewis at centraldesktop.com> *Central Desktop. Work together in ways you never thought possible.* Connect with us Website <http://www.centraldesktop.com/> | Twitter <http://www.twitter.com/centraldesktop> | Facebook <http://www.facebook.com/CentralDesktop> | LinkedIn <http://www.linkedin.com/groups?gid=147417> | Blog <http://cdblog.centraldesktop.com/> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140513/b0be393f/attachment.htm>
 |